Lightweight and portable flotation devices, including pontoon boats, kick boats, float tubes, etc. have been increasingly popular in recent years, particularly with sport fishermen and white-water enthusiasts. Most of these devices rely upon inflatable tubes, pontoons, or bladders that consist of a thin, flexible membrane filled with pressurized air. These prior art devices are very lightweight and easily portable, and may be folded into a relatively compact shape. Prior art pontoons which are formed of a thin membrane such as vinyl are typically 0.015 inch thick. Others, such as polyurethane film are even thinner, such as about 0.009 inch. Such pontoons are generally uniform in thickness throughout, and are frequently heat-welded together from several flat pieces to form the tubular shape.
Because they are relatively thin, typical float tubes and pontoons are highly susceptible to puncture, such as from snagging fish hooks, rocks, branches, etc. Additionally, the sections of their construction are typically heat-welded together, creating seams that can present inherent weakness. Because of their thinness and pliability, when typical pontoons are punctured, they can collapse and lose their buoyancy. They can also be difficult to repair. Typical thin membrane pontoons are repaired in a manner similar to bicycle or automobile tires, using patches and chemical adhesives. Once repaired, the membrane may not be as strong as it was before.
Additionally, typical float tubes and pontoons are very susceptible to changes in temperature and barometric pressure. For example, many users first inflate their boat in the morning, when temperatures are cool. Then, by afternoon, when the ambient temperature has increased, the pontoon pressure will have increased such that air must be released from the pontoon to prevent it from bursting. When temperatures decrease again later in the day and toward evening, the pontoon pressure likewise drops, and the boat may no longer provide sufficient buoyancy.
Similarly, many pontoon boat users inflate their pontoons before leaving home, and then drive into a mountainous region at much higher altitude. In the course of gaining altitude, the barometric pressure and temperature will typically drop, increasing the relative pressure inside the pontoons, sometimes enough to cause the pontoon to burst.
Another problem with many prior art pontoons is that they are unnecessarily complex in their design.